Introduction of a low fuel consumption technique such as downsizing turbos and idling stop decreases an intake pipe negative pressure (pump loss) of an internal combustion engine, and results in difficulty in emitting (evaporative fuel purge) a volatile fuel (evaporative fuel) in a fuel tank by the negative pressure of the intake pipe of the internal combustion engine. Hence, PTL 1 discloses a method for stopping fuel injection to an internal combustion engine by way of idling stop, and performing evaporative fuel purge during a period in which an internal combustion engine rotational speed becomes a predetermined value or less to realize both of reduction of fuel consumption by way of idling stop and evaporative fuel purge.